Photodissociation of Molecular Oxygen (O2)
This movie shows how ultraviolet "light" can break apart a molecule. You need the latest version of the Flash player to see this movie.
Photons are little bits of light. Photons carry energy.
When a photon hits an oxygen molecule, it adds energy to the molecule. The molecule has chemical bonds (they work a bit like stretchy rubber bands!) holding its atoms together. Sometimes the energy from the photon breaks the bond between the two oxygen atoms. The atoms fly apart! This is called photodissociation.
Photons of ultraviolet (UV) light carry more energy than photons of visible light carry. It takes high-energy UV photons to break oxygen apart!
Photodissociation of Molecular Nitrogen
Photodissociation of Water
Photodissociation of the Hydroxyl Radical
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